'''
Created on 2013-5-13

@author: darcywang
'''

import re

def plural(noun):
    if re.search('[sxz]$',noun):
        return re.sub('[sxz]$','es',noun)
    elif re.search('[^aeioudgkprt]h$', noun):
        return re.sub("$","es", noun)
    elif re.search('[^aeiou]y$', noun):
        return re.sub("y$","ies", noun)
    else:
        return noun + "s"
    

if __name__ == '__main__':
    print plural("watch")